The present invention relates to a tape type disposable diaper, which has no front target tape on the outer face of the front of the diaper and which can adjust its size slightly.
In the prior art, the commercially available tape type paper diaper is provided with diaper wearing fastening tapes 50 and 50 on the two sides of the back of the paper diaper, for example, as shown in FIG. 16. When the paper diaper is used, its front and back are individually applied to the body of the wearer. After this, the aforementioned fastening tapes 50 and 50 are brought to the abdomen side, and are fastened to a front target tape 51 (as will be called the FTT), which is made of a plastic material such as polyethylene, a nonwoven fabric or a tricot and fixed by an adhesive agent to the surface of a liquid-impermeable sheet such as a polyethylene sheet of the outer face of the paper diaper (as referred to the following Patent Documents 1 and 2, for example).
It is hard to wear the paper diaper of this tape type snugly by a single fastening operation. As a matter of fact, it frequently occurs that the diaper is worn by several fastening operations. After one fastening tape 50 was fastened to the FTT 51, the other fastening tape 50 may fail to reach the FTT. In this case, it is troublesome to renew the fastening operation, and these several renewing operations may break the FTT.
In order to cope with these problems, there have been various disposable diapers, in which the aforementioned fastening tapes 50 are made not into the adhesion type but into a mechanical engagement type using hooks or the like, in which the back sheet constituting the outer face of the diaper is made of a nonwoven fabric, so that the aforementioned fastening tapes 50 are brought, when the diaper is worn, into direct engagement with the surface of the aforementioned outer-face back sheet (or a nonwoven fabric).
In the following Patent Document 3, for example, there is disclosed a disposable diaper comprising: a liquid-permeable surface sheet, a liquid-impermeable back sheet; an absorbing member interposed between those two sheets; fastening tapes for fixing the diaper when the diaper is worn; and release tapes for folding back the aforementioned fastening tapes, when unneeded, with folding-back portions to adhere their adhesive faces, wherein the aforementioned back sheet has a load of 100 g/cm to 300 g/cm at the extension of 3% of the aforementioned disposable diaper in the widthwise direction, a bulk softness of 55 g or less and a breakage strength of 250 g/cm or more; wherein the aforementioned fastening tapes have a 180-degree peeling force (i.e., a peeling force after lapse of 24 hours of RH at 40° C. and 80% after the adhesion to the aforementioned back sheet) of 400 g/cm or less and a holding time of 10 minutes or longer under a load of 500 g; and wherein the aforementioned back sheet has no reinforcing film for adhering the aforementioned fastening tapes.
In the following Patent Document 4,on the other hand, there is disclosed a paper diaper comprising an outer-face sheet having fastening members attached to the two back-side end portions of the paper diaper and hook elements on the fastening faces of the fastening members and forming the back of the aforementioned paper diaper which is made of a nonwoven fabric, wherein the hook elements of the aforementioned fastening members can engage, when the paper diaper is worn, with arbitrary portions of the surface of the aforementioned nonwoven fabric outer-face sheet. In the paper diaper, a target print for guiding the positions, at which the hook elements of the aforementioned fastening members are fastened, is so applied to at least one of the aforementioned nonwoven fabric outer-face sheet and the lower-side sheet as can be viewed from the outside.
In the following Patent Document 5, moreover, there is provided a disposable paper diaper of an FTT-less type, which is constituted such that the front and the back are formed by folding a diaper body including a liquid-permeable top sheet for covering the surface side, a liquid-impermeable back sheet for covering the back side, an absorbing member interposed between the aforementioned individual sheets, and diaper fastening tapes fixed on the two sides of the outer-side back portion of the aforementioned back sheet. In the disposable paper diaper, band-shaped sheets having a target print indicating the fastening positions of the fastening tapes are so disposed at the abdomen position of the aforementioned front that the print can be viewed from the outside.
Patent Document 1: JP-A-7-328069
Patent Document 2: JP-A-7-313552
Patent Document 3: JP-A-7-308343
Patent Document 4: JP-A-2002-253608
Patent Document 5: JP-A-2003-153952
In case, however, the mechanical type fastening tapes are brought into direct engagement with the nonwoven fabric forming the outer-face back sheet, as in the disposable diapers disclosed in the aforementioned Patent Documents 1 to 5, the engaging force between the mechanical type fastening tapes and the outer-face back sheet cannot be sufficiently retained, and the mechanical type fastening tapes may come out, while the diaper being worn, from the outer-face back sheet.
Moreover, the outer-face back sheet and the leakage-preventing sheet, as arranged on the inner-face side of the back sheet, are pattern-adhered by a hot-melt adhesive. When the aforementioned mechanical type fastening tapes are re-attached several times, there arises a problem that the aforementioned outer-face back sheet peels off the leakage-preventing sheet. Against this problem, the aforementioned Patent Document 2 subjects the fastened range to a dot-shaped embossing treatment thereby to prevent the outer-face back sheet from peeling off the leakage-preventing sheet. However, the embossing treatment makes the sheet hard thereby to cause a problem that the wearing feel is deteriorated. Moreover, a homogeneous application of the hot-melt adhesive and an increase in the quantity of application could also prevent the outer-face back sheet and the leakage-preventing sheet from peeling off. In this case, too, there arises a problem that the adhesive makes the sheet hard to deteriorate the wearing feel.
Moreover, a plurality of kinds of the tape type paper diaper of sizes for infants to LL are prepared according to the ages (or body sizes) of babies. In case, however, the body size of a baby is located intermediate of the sizes prepared, the paper diaper may fail to fit the body size thereby to establish a clearance from the body.
Therefore, a major object of the invention is to provide a disposable diaper, in which mechanical joining type fastening tapes are disposed on the two side portions of the back of the diaper and are brought, when the diaper is worn, into direct engagement with the surface of an outer-face back sheet (or a nonwoven fabric) made of the nonwoven fabric, so that the force of the fastening tapes to engage with the outer-face back sheet is improved without being accompanied by a drastic design change in the aforementioned outer-face back sheet and the fastening tapes.